Michael G. Macdonald, who spent 26 years at the Defense Department in managerial roles and participated in shaping Cold War defense policy and strategy, died Dec. 5 at his home in Warrenton, Va. He was 83.

The cause was Parkinson’s disease, said his son Quintin Macdonald.

Mr. Macdonald joined the Defense Department in the early 1960s and held supervisory management positions in the foreign military sales program.

He lead the U.S. negotiating team that successfully concluded the sale of F-16 fighter aircraft to NATO consortium countries, his family said. He also was included in the first U.S. delegation to China after President Richard M. Nixon’s groundbreaking 1972 visit, his family said.

He was assigned to the State Department as politico-military attache at the U.S. Embassy in London from 1975 to 1978. Mr. Macdonald later focused on chemical and biological arms-control matters and was the Pentagon’s U.S. delegation representative in the mid-1980s at the Conference on Disarmament in Geneva.

He retired in 1987 and settled on a historic property in Warrenton.

Michael Graeme Sylvester Macdonald was born in Nottingham, England. Before he became a U.S. citizen in the mid-1950s, he served in the U.S. Army as a tank commander during the Korean War.

After graduating from the University of California at Berkeley, he worked for the Institute for Defense Analyses and the Stanford Research Institute on defense-related concerns.

His wife of 51 years, Katharine Kolasa “Kay” Macdonald, died in 2005. Their son Ian G. Macdonald died in 2006.

Survivors include four children, Linda Rich of Orlean, Va., Mark Macdonald of Bath, England, Keith Macdonald of Warrenton and Quintin Macdonald of Nashville; two brothers; six grandchildren; and two great-grandchildren.

— Adam Bernstein